I actually resolved the issue shortly before you responded. The issue was a power problem. I am using the computer’s USB for power to both the maestro and the motor since both use under 500mA of combined current. If I use the hub’s external power supply, which sources 2A, the maestro and the motor return to normal operation. It seems as though hubs must not use a general power plane from which all ports can draw power, that rather they ration off power to each port even if the ports aren’t being used.
Sorry for the false hub communication alarm. 